chain ang gear driven wind turbines with oil bath chain case

[Bio Diesel Man]

Hi All,  I have been looking at possible building a wind turbine/axial flux design with C8 ceramic magnets. I have been following Chris Olsons progress with his turbines and it looks like me might be on to something. As the ceramic magnets are cheap when compared to neo. magnets, and with the gear drive system he is turning the generator up to 1000 to 1200 R.P.M.  And he is getting 2KW to 3KW> out of these machines.. Granted the chain and sprockets cost money and the bearings to, but he says that he has had his turbine up for over 2 years and the oil bath chain drive is holding up great..So I was wondering if anyone else is looking at a system like this and was wondering what your take is in doing this..    Thanks for this great informative site too!             Duff Streeter  Bio Diesel Man

[ChrisOlson]

Duff, I don't know of anybody else that has done it to the same extent I have.  Like I have told other folks, it takes a careful match of components to make it work.  But when you can get this sort of power from a 10 foot turbine with ferrite magnets @ 25 mph wind speed on a 24 volt system, there is no doubt that if you do your engineering homework, that it does work.



But I have to point out that the MidNite Classic 150 controller is the other part of the puzzle with the latest very high-performance turbines I am building.

A lot of folks here will downplay geared turbines because there's "losses" in the drivetrain, and they don't have the facilities to build one.  To make it work you have to design a generator that operates at higher efficiency and thereby outweighs gearing losses.  You can't just throw any random combination of gearing at it and get it work.  It's an integral design in matching the rotor to the generator to get the most from the shaft power developed by the rotor.
--
Chris

[Bio Diesel Man]

Chris,    Yes the power you are getting from a 10 foot turbine is great..  I understand that you will have some losses in a geared turbine ,but when you can use ferrite magnets to get that kind of output,,,well I would say that is really something.I do have the shop and tools to put one together,though I am not a ma chinest by trade,I can usually get things figured out with the tools I have..I have a large lathe over 30 inchs of swing, and also a smaller one.A bridgeport.large drillpress, shear,.break, and lots of welding equipment,as I am a welder fabricator,ect..I was thinking about a machine with a 20 1/2 inch magnet rotors,using C8 ceramics 1 1/2 inchs wide by 4 inch's long.16  magnets on each rotor,and 12 coils..Also was thinking about making my stator thinner,around 3/8 of an inch thick,which will give me more flux pull because the distance between magnet rotors would be less than most machines I have read about.. Also with a machine that size  it would allow me to make fairly large coils ,by making them thinner but also making them wider.Each leg on a coil could be around 1 3/16 or so wide.. With this type of machine I should have good flux,and a good output from the coils as well..The machine would be 3 phase like most of the ones I have read about.. I don"t  know anything about the Mppt controler you talk about..But was wondering if you just charged batteries and than run through an inverter ,,how much more efficient would your mppt set up be  over a battery charging system,,all things except the controller being equill..  Thanks  Duff  Bio Diesel Man

[jlt]

          For a first turbine going to a chain driven machine would be a great undertaking
Expressly of of that size.
 
           The price of NEO mag's  Is not that much considering the overall cost of the mill and tower.
Last time I checked the price of 1x2x1/2 mags were about 8 bucks.And they are stronger than the huge ferrite you are thinking about.
             Simple direct drive  are much simpler to build.
                     Jlt   

[ChrisOlson]

But was wondering if you just charged batteries and than run through an inverter ,,how much more efficient would your mppt set up be  over a battery charging system,,all things except the controller being equill..

We live off-grid and the batteries and inverters are all we got (except for the generator).  The MPPT allows the turbine to run at much higher voltage than battery bank voltage, and it steps the high voltage power down to bank voltage for charging.
--
Chris

[NoSmoke]

I've experimented with both roller chain and direct drive.  My first used ferrite mags in a motor conversion and was driven by a two stage chain drive with overall ration of about 5 to 1.  The gear ratio was chosen to get 120VAC at top speed.   I then converted it to neos, cramming in as much magnet as I could and ran it direct but could only get about 80VAC.  I'm about to try a third scenario with about 1/2 the neos as before and a single stage chain.

A single stage chain drive is not difficult at all to flange up - all you need extra is two sprockets and the chain.  I did not have any sort of lube system and just sprayed everything with roller chain lube every few months or so.  I have noticed very little wear over about a year of operation so the concept seems sound to me.  Motorcycles have been used for many years with chain drives with no big problems and I would expect under much tougher conditions.

As for losses, if one assumes 10% loss in the chain drive, just increase blade length by 3% to compensate.

[Flux]

Before you rebuild the magnet rotor, why don't you try the chain drive with a smaller ratio  to get you back to 120v with the present neo rotor. If it doesn't work out you only need to change the sprockets for the new rotor.

Flux

[Bio Diesel Man]

The chain drive is a great way to go,I think with a chain case with oil bath like Chris is doing..Otherwise the chain drive with sprockets will be a pain as the chain and sprockets wear,you will be tightening the loose chain all the time..I did that about 20 some years ago with a 4KW winco generator  1800 RPM unit, chain driven with a 6.8 to 1 gear ratio.. It had  14 foot prop,and would charge a 36 volt battery bank.. It worked but not as good as a permanent magnet machine will like Chris is building.. Also my winco generator had brushes and slip rings in it  because it was a wire wound 4 pole field type of generator.. The problem with this type of generator is once you get up to cut in speed it took a lot of wind to make it charge much over 10  amps.So not really all that efficient for that off the shelf 1800 RPM generator..  With Chris"s design using lots of magnet poles you can start making power at a lower RPM and the permanent magnet design  just seems like a much better unit..Granted you have to aslo match the coil sixe and rotor size to get an efficient machine.. Anyway that is just my ideas and welcome all feedback.. Thanks, Duff/  Bio Diesel Man

[ChrisOlson]

The oil bath eliminates adjustments, maintenance and noise.  It can be considered pretty much like the timing chains used in Detroit built V-8 engines for better than six decades.

..I did that about 20 some years ago with a 4KW winco generator

An old 36 volt 14 foot Winco Wincharger?  Do you have any idea how much money those are worth today if you still had it flying condition?
--
Chris

[NoSmoke]

Before you rebuild the magnet rotor, why don't you try the chain drive with a smaller ratio  to get you back to 120v with the present neo rotor. If it doesn't work out you only need to change the sprockets for the new rotor.

Flux

Long story short, I tried to make curved neos by gluing two 1/2x1/2x2" neos together (with a wedge shaped gap to provide the curvature).  It was a bear holding them together until the epoxy cured but it sort of worked using strips of iron to short the flux and a vise.  Once assembled the combo neos where epoxied onto the turned down rotor lams.  Trouble was it worked for a while but some of the neos came apart and rubbed on the stator.  So, redid it with one row of two single neos per pole (8 poles).

Output per rev is not as high but OTOH, magnetic drag is a lot lower.  I'm not sure however if lower magnetic drive is a particular advantage as the rotor has to be spun faster so the RPM x drag force might be equal or similar in each case(?).

I'd like to see some details on an oil bath arrangement.  My main concern would be sealing at the shafts - are there DIY shaft seals available that might work w/o a lot of drag?

[Bio Diesel Man]

 ???Chris, If I could have only been able to look into the future!! Back them I was much younger and stupid..Now I am much older and still !?*%$# well whatever..  The question I have is do you think the 20 1/2 inch magnet rotors would be to large for a 16 pole machine using 1 1/2 inch wide x 4inch long ceramic 8 magnets 1 inch thick??   My calculations   say that they should fit the magnet rotor disk O.K...And if I form my coils in the v shape like you are using..Also it should allow me to make the coils thinner but also allows room to make the coils wider so I can keep the magnet rotors closer together,,,more flux,,, more power??/I was thinking about casting the stator 3/8 of an inch in thickness,,no thicker, to allow the magnet rotors a closer air gap.. What is your take on trying something like this??  Duff  Bio Diesel Man

[ChrisOlson]

Duff, I always try anything.  And it sounds fine to me.  4" is a little longer than I'd use (1.5 x 3" would be better) but you can't get ferrite magnets in too many custom sizes and shapes.
--
Chris

[Bio Diesel Man]

Chris,    I get my magnets from Adams Magnetics,,,Elmhurst,Illinois.Phone#1 630-617-8880/These folks will cut and shape them for you and magnetize however you want. They are great people to work with..  And they are here in the U.S.A.  I am looking at ordering shaft stock,bearings, and sprockets,as time allows.  Hope you are having nice weather there in Wisconsin.Here in Mi. we just got hammered with a big bunch of heavy snow.   I hope this magnet source will help out all who are doing this kind of work.. Duff/Bio Diesel Man